In the reaction $SO_{2(g)} + 1/2 O_{2(g)} \to SO_{3(g)}$,how many liters of air at $STP$ are required for the complete conversion of $6.4 \, g$ of $SO_2$ to $SO_3$ (in $, L$)? (Assume air contains $20 \% \, O_2$ by volume).

If an $LPG$ cylinder contains a mixture of butane and isobutane,what is the amount of oxygen required for the combustion of $1 \ kg$ of this mixture in $kg$?

Diatoms,microscopic organisms,are an abundant food source in the oceans producing carbohydrates from carbon dioxide and water by photosynthesis.
$6CO_2 + 6H_2O + \text{solar energy} \to C_6H_{12}O_6 + 6O_2$
$A$ blue whale gains $75 kg$ of mass per day by feeding on krill. The whale must consume ten times this mass of krill each day. The krill must consume $10.0 kg$ of diatoms to produce $1.0 kg$ of krill. Assuming that the mass gain of a whale's life is due to the consumption of carbohydrates $(C_6H_{12}O_6)$,calculate the moles of $CO_2$ that must be used by the diatoms to produce the carbohydrates consumed by a blue whale in a day.

The reaction of calcium with water is represented by the equation $Ca + 2H_2O \to Ca(OH)_2 + H_2$. What volume of $H_2$ at $STP$ would be liberated when $8 \ g$ of calcium completely reacts with water? .......... $cm^3$

$20 \ g$ of iron pyrite,$FeS_2$,is roasted completely and the $SO_2$ gas produced is absorbed completely in $400 \ mL$ of $NaOH$ solution. If only $50\%$ of the $NaOH$ is used in the reaction,what was the molarity of the $NaOH$ solution?

The number of molecules in $100 \, mL$ of $0.02 \, N$ $H_2SO_4$ is .....